Actuating devices of this type have become known from the Applicant's French publication FR-A-24,96,142 or German publication DE-A-34,22,315. These permit flushing of a toilet that can be interrupted and consequently allow the adjustment of the amount of flushing water to the particular case. It is thus possible to considerably reduce the fresh water consumption compared with the ordinary flush tank in which flushing cannot be interrupted. Since this is ecologically and economically meaningful and advantageous, flush tanks in which flushing can be interrupted have found widespread use. However, especially in the case of flush tanks made from ceramic, there is now a difficulty due to the fact that the mounting of such actuating devices is very complicated as a consequence of the large dimensional tolerances that are common. For example, it is necessary to cut two connecting rods to an exact size for mounting in the case of the actuating device according to the above-mentioned DE-A-34,22,315.